81953532 has 60 divisors (see below), whose sum is σ = 226860480. Its totient is φ = 25709184.

The previous prime is 81953513. The next prime is 81953533. The reversal of 81953532 is 23535918.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81953533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1932 + ... + 12947.

It is an arithmetic number, because the mean of its divisors is an integer number (3781008).

Almost surely, 2^81953532 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81953532, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113430240).

81953532 is an abundant number, since it is smaller than the sum of its proper divisors (144906948).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81953532 is a wasteful number, since it uses less digits than its factorization.

81953532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14912 (or 14901 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 81953532 is about 9052.8190084636. The cubic root of 81953532 is about 434.3660682876.

The spelling of 81953532 in words is "eighty-one million, nine hundred fifty-three thousand, five hundred thirty-two".